TITLE
Recommendation to receive and file the report, “Elevation Changes in the City of Long Beach, May 2014 through October 2014." (Citywide)
DISCUSSION
The City of Long Beach, through the Long Beach Gas and Oil Department (LBGO), supervises oil production and subsidence control operations in the Wilmington Oil Field. LBGO conducts elevation surveys every six months to monitor elevation changes in the oil fields and adjacent city areas. This report focuses on elevation changes that have occurred from May 2014 through October 2014. The LBGO survey includes the following areas: Civic Center, Central City, Alamitos Bay, Naples, Harbor District, and the offshore area encompassing the four oil islands.
The results of the six-month survey show that elevations were stable in the Civic Center, Central City, Alamitos Bay, and Naples. The offshore area was stable except for Island White which experienced a decline of 0.06 foot (0.7 inch). The decline is within normal limits and not expected to continue. In the Harbor District, Piers D, E, H, S, and the eastern portion of Pier T experienced a decline of up to 0.09 foot (1.1 inch). Active oil field development in the area may have contributed to the decline. A mitigation plan, based on adjustments of oil field operations, has been implemented and the area will be closely monitored for further action.
The LBGO survey uses a series of benchmarks to determine elevation changes. Studies by the Department’s engineers and geologists show that the benchmarks may rise and fall in such a manner as to make a survey either optimistic (slightly up in elevation) or pessimistic (slightly down in elevation). These changes in elevations may be associated with tidal cycles, temperature changes, and/or deep earth tectonic changes or re-pressuring operations. Surface elevations over the active Wilmington Oil Field can be expected to fluctuate under changing water flood conditions.
This matter was reviewed by Deputy City Attorne...
Click here for full text